Callaspo, who is hitting .252 with five home runs and 36 runs batted in, is expected to play second base for the A’s, a position he hasn’t played on a full-time basis since 2009 with the Kansas City Royals.

The trade became official shortly after Callaspo was pulled from Tuesday's game against the Texas Rangers in the fifth inning.

Green, a first-round pick (13th overall) in 2009, hit .325 with a .379 on-base percentage, .500 slugging percentage, 11 homers and 50 RBIs in 87 games for triple-A Sacramento this season but has struggled to find a position.

Green was drafted as a shortstop but played the outfield, first base and second base in the minor leagues. He played five games at second base for the A’s this season.

The Angels are expected to recall infielder Chris Nelson from triple-A Salt Lake to take Callaspo's spot. Nelson was pulled from his minor league game moments after Callaspo was pulled from the Angels' game.